Method for the preparation of salts of L-ornithine

Abstract

Salts of L-ornithine are prepared by means of the enzymatic conversion of arginine to L-ornithine in the presence of the enzyme L-arginase in an aqueous medium in such a manner that the acid whose salt is to be prepared is used for the adjustment of the pH for the enzymatic conversion and for the subsequent neutralization of the reaction mixture and that the salt formed is isolated directly from the reaction mixture.

What is claimed is: 
     
       1. A method for the preparation of salts of L-ornithine which comprises enzymatically converting arginine into L-ornithine in the presence of the enzyme L-arginase in an aqueous reaction medium and subsequently forming the salt; said process consisting of the steps of: a) adjusting a pH of said aqueous reaction medium to a range between 8.0 and 10.0 prior to the enzymatic process with an acid of the salt to be produced;   b) maintaining the pH between 8.0 and 10.0 during the enzymatic conversion with the same acid as used in step (a);   c) adjusting the pH of said aqueous reaction medium after said enzymatic conversion to a range between 6.5 and 7.0 with the same acid as used in step (a); and   d) allowing the L-ornithine salt to crystalize from said aqueous reaction medium; and   e) recovering the crystals formed.   
     
     
       2. A method as set forth in claim 1 further consisting of the step of removing the enzyme from the reaction mixture by ultrafiltration prior to the crystallization of the L-ornithine salt.